/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1995-1998 Søren Schmidt
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer,
 *    without modification, immediately at the beginning of the file.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/module.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/consio.h>
#include <sys/fbio.h>
#include <sys/resourcevar.h>
#include <sys/smp.h>

#include <machine/pc/display.h>

#include <dev/fb/fbreg.h>
#include <dev/fb/splashreg.h>
#include <dev/syscons/syscons.h>

static u_char   *message;
static int      *messagep;
static int      messagelen;
static int      blanked;

#define MSGBUF_LEN      70

static int      nofancy = 0;
TUNABLE_INT("hw.syscons.saver_snake_nofancy", &nofancy);

#define FANCY_SNAKE     (!nofancy)
#define LOAD_HIGH(ld)   (((ld * 100 + FSCALE / 2) >> FSHIFT) / 100)
#define LOAD_LOW(ld)    (((ld * 100 + FSCALE / 2) >> FSHIFT) % 100)

static inline void update_msg(void);

static int
snake_saver(video_adapter_t *adp, int blank)
{
        static int      dirx, diry;
        int             f, color, load;
        sc_softc_t      *sc;
        scr_stat        *scp;

/* XXX hack for minimal changes. */
#define save    message
#define savs    messagep

        sc = sc_find_softc(adp, NULL);
        if (sc == NULL)
                return EAGAIN;
        scp = sc->cur_scp;

        if (blank) {
                if (adp->va_info.vi_flags & V_INFO_GRAPHICS)
                        return EAGAIN;
                if (blanked <= 0) {
                        sc_vtb_clear(&scp->scr, sc->scr_map[0x20],
                                     (FG_LIGHTGREY | BG_BLACK) << 8);
                        vidd_set_hw_cursor(adp, -1, -1);
                        sc_set_border(scp, 0);
                        dirx = (scp->xpos ? 1 : -1);
                        diry = (scp->ypos ?
                                scp->xsize : -scp->xsize);
                        for (f=0; f< messagelen; f++)
                                savs[f] = scp->xpos + scp->ypos*scp->xsize;
                        sc_vtb_putc(&scp->scr, savs[0], sc->scr_map[*save],
                                    (FG_LIGHTGREY | BG_BLACK) << 8);
                        blanked = 1;
                }
                if (blanked++ < 4)
                        return 0;
                blanked = 1;
                sc_vtb_putc(&scp->scr, savs[messagelen - 1], sc->scr_map[0x20],
                            (FG_LIGHTGREY | BG_BLACK) << 8);
                for (f=messagelen-1; f > 0; f--)
                        savs[f] = savs[f-1];
                f = savs[0];
                if ((f % scp->xsize) == 0 ||
                    (f % scp->xsize) == scp->xsize - 1 ||
                    (random() % 50) == 0)
                        dirx = -dirx;
                if ((f / scp->xsize) == 0 ||
                    (f / scp->xsize) == scp->ysize - 1 ||
                    (random() % 20) == 0)
                        diry = -diry;
                savs[0] += dirx + diry;
                if (FANCY_SNAKE) {
                        update_msg();
                        load = ((averunnable.ldavg[0] * 100 + FSCALE / 2) >> FSHIFT);
                        if (load == 0)
                                color = FG_LIGHTGREY | BG_BLACK;
                        else if (load / mp_ncpus <= 50)
                                color = FG_LIGHTGREEN | BG_BLACK;
                        else if (load / mp_ncpus <= 75)
                                color = FG_YELLOW | BG_BLACK;
                        else if (load / mp_ncpus <= 99)
                                color = FG_LIGHTRED | BG_BLACK;
                        else
                                color = FG_RED | FG_BLINK | BG_BLACK;
                } else
                        color = FG_LIGHTGREY | BG_BLACK;

                for (f=messagelen-1; f>=0; f--)
                        sc_vtb_putc(&scp->scr, savs[f], sc->scr_map[save[f]],
                                    color << 8);
        } else
                blanked = 0;

        return 0;
}

static inline void
update_msg(void)
{
        if (!FANCY_SNAKE) {
                messagelen = sprintf(message, "%s %s", ostype, osrelease);
                return;
        }
        messagelen = snprintf(message, MSGBUF_LEN,
            "%s %s (%d.%02d %d.%02d, %d.%02d)",
            ostype, osrelease,
            LOAD_HIGH(averunnable.ldavg[0]), LOAD_LOW(averunnable.ldavg[0]),
            LOAD_HIGH(averunnable.ldavg[1]), LOAD_LOW(averunnable.ldavg[1]),
            LOAD_HIGH(averunnable.ldavg[2]), LOAD_LOW(averunnable.ldavg[2]));
}

static int
snake_init(video_adapter_t *adp)
{
        message = malloc(MSGBUF_LEN, M_DEVBUF, M_WAITOK);
        messagep = malloc(MSGBUF_LEN * sizeof *messagep, M_DEVBUF, M_WAITOK);
        update_msg();
        return 0;
}

static int
snake_term(video_adapter_t *adp)
{
        free(message, M_DEVBUF);
        free(messagep, M_DEVBUF);
        return 0;
}

static scrn_saver_t snake_module = {
        "snake_saver", snake_init, snake_term, snake_saver, NULL,
};

SAVER_MODULE(snake_saver, snake_module);